Here’s a low-ripple and low-noise 48V regulated phantom energy provide for an audio preamplifier and driver. Such energy provides require well-filtered, low-ripple and low-noise output voltage with present lower than 200mA. These are comparatively uncommon and costly. Offered right here is an easy and low-cost answer appropriate for a lot of functions together with take a look at tools and audio functions.
Circuit and dealing
The circuit diagram of the 48V regulated energy provide with low ripple and low noise is proven in Fig. 1. It’s constructed round bridge rectifier BR1, voltage regulator TL783 (IC1), three rectifier diodes 1N4004 (D1 by way of D3) and some different parts.
Fig. 1: Circuit diagram of the 48V regulated energy provide
TL783 is a high-voltage adjustable voltage regulator that may present voltage from 1.2V to 125V and output present as much as round 700mA. Its inside reference voltage is 1.25V, and minimal output present is 15mA. That’s the reason the worth of resistor R7 is 82ohm (1.25V/82ohm=15.24mA).
Most energy dissipation of TL783 will depend on TO-220 package deal and its heat-sink. Right here, a further heat-sink with thermal resistance decrease than 10°C/W is used. Output voltage of TL783 might be calculated utilizing the approximate relationship:
Enter 230V AC mains is utilized to connector CON1.
AC mains enter is protected with fuse F1. Mains AC voltage could have vital noise. Enter noise filter is constructed round capacitors C1 and C2, resistors R1 and R2, and inductors L1 and L2.
Transformer X1 is rated as 230V AC main to 60V, 1A secondary.
Resistors and capacitors R3, R4, C3, R5, C4 and R6 present some filtering of the noise from AC mains and from the switching of diodes in BR1. Capacitors C5, C6, C7 and C8 filter the rectified voltage. Additionally, C9 and C10 cut back the noise from IC1. Diodes D1, D2 and D3 defend IC1. Resistors R7 and R8 repair output regulated voltage Vout. Inductor L4 and capacitors C13 and C14 additional filter output voltage from IC1.
The circuit has three outputs (O/P1 by way of O/P3), with 48V phantom energy provide from every to drive as much as three completely different circuit functions. LED1 exhibits the presence of output voltage.
Development and testing
A PCB format for the 48V regulated energy provide is proven in Fig. 2 and its parts format in Fig. three. After assembling the circuit on the PCB, enclose it in an appropriate cupboard.
Fig. 2: PCB format of the 48V regulated energy provideFig. three: Elements format for the PCB
Repair transformer X1 on the physique of the cupboard, and join its main and secondary on the PCB. Additionally, join 230V AC mains throughout CON1. Repair LED1 on the entrance panel, and CON2 by way of CON4 on the rear aspect for the output hundreds.
The circuit doesn’t want any adjustment to function correctly.
Petre Tzv Petrov was a researcher and assistant professor in Technical College of Sofia (Bulgaria) and expert-lecturer in OFPPT(Casablance), Kingdom of Morocco. Now he’s working as an electronics engineer within the non-public sector in Bulgaria.